Sealed switch and actuator assembly



March 17, 1959 A. W. HAYDON ETAL SEALED SWITCH AND ACTUATOR ASSEMBLYFIG.

Filed June 7. 1956 Il! III INVENTORS ARTHUR W. HAYDON THEODORE YKORSGREN SR.

ATTORNEYS United States Patent O SEALED SWITCH AND ACTUATOR ASSEMBLYArthur W. Haydon, Milford, and Theodore Y. Korsgren, Sr., Woodbury,Conn., assignors to Haydon Switch, Inc., Waterbury, Conn., a corporationof Connecticut Application June 7, 1956, Serial No. 590,039 14 claims.`(cl. zoo- 168) The present invention relates to electrical switchingdevices, and more particularly to improved arrangements for effectingthe actuation of hermetically sealed switch assemblies.

Where switch assemblies are employed in aircraft, for example, it isgenerally desirable and often necessary to hermetically seal th/e switchto avoid the etects of moisture condensation, freezing and the like. Thepresent invention is directed to an improved assembly wherein criticalparts of the switch apparatus are more effectively sealed.

One of the improved features of the invention resides in the provisionof a switch assembly comprising a switch mechanism mounted within acasing which is generally sealed but which has an opening therein forreceiving a rotatable control member used in actuating the switch. Theimproved apparatus includes a novel Iarrangement for providing a sealabout the rotary control element in such manner that the critical partsof the switch actuating mechanism are located within thesealed casing.`With this arrangement it is possible to eliminate icing of the moredelicate components of the actuating mechanism as might otherwise occurwhen the switch assembly isem: ployed in aircraft, for example.`

; As one of its more specific improved features, the new apparatusincludes a4 rotary control member having an eccentric portion which is1generally surrounded by a` tubular` sealing element secured at one endabout the opening in the casing through Which the control memberextends. A switch is actuated by means of the eccentric portion of thecontrol member acting, in some casesdirectly through the sealing elementand in other `cases vthrough additional elements which` are secured tothe sealing element.

f For a better understanding ofthe invention, reference may be made tothe accompanying drawings, in which:

Fig. 1 is a` cross-sectional view of aswitch assembly constructed inaccordance with the invention; p p

Fig.` 2 is a fragmentary cross-sectional view taken along line 2-2 ofFig. 1; t

Figs. 3 and 4 are fragmentary cross-sectional views of modified forms ofthe new assembly; and

`ligs. 5 and6 are cross-sectional views of further modifications of thenew assembly. A u

i Referring initially to Figs. 1 andr2, the numeral `10 designates acasing, which may bea steel stamping for example.` Mounted within thecasing is a switch 11, which may have a mechanism similar` tothatdisclosed in the copending application of Arthur .W. Haydon, SerialNo. 362,505, led lune 18, 1953, for Suap Action Switch, now U. S. PatentNo. 2,773,954, issued December 11, l1956. The switch 11, in itself,`need not be hermetically sealed, andthas terminal posts 12, 13extending through the back wall 14 of the casing, through seals 15 ofglass or other suitable material. At the top of the switch 11 is anactuating plunger 16 which is adapted with a limited vertical movementto electA the opening 'and `closing of the switch contacts.

i of the sleeve 19, so that the member is positioned in At the front ofthe casing 10 is a cover plate 17, and, in the completed assembly, thecover 17 is brazed or soldered to the side walls of the casing to forman air tight seal therewith. Above the switch 11, the cover plate 17 hasan opening 18 in which is received and se. cured a bearing sleeve 19.The sleeve 19 has a ange 19a intermediate its ends engaging the frontface of the cover 17 and having a threaded portion 19b extendingoutwardly from the cover. The inner end of the sleeve 19 extends partlyover the top of the switch 11 and has an annular groove 19e at its outersurface.

A control member 20, having a cylindrical portion 21, is received andjournaled by the sleeve 19. The control member 20 has a flange 22 at theouter end of the cylindrical portion 21 which engages the outer endsurface proper axial relation to the sleeve. A threaded cap 23 engagesthe threaded outer portion 19b of the sleeve 19` to retain controlmember 20 in the` desired axial position while permitting rotation ofthe member. The outer end of the control member 20 may be knurled orotherwise machined, as at 24, to receive a suitable control knob, notshown. A

At the inner end of the control member 20 is an eccentric spindle 25disposed in parallel relation to the axis of rotation of the controlmember 20 and prefer-` ably forming an integral part thereof. Theforward end portion of the eccentric spindle 25 rotatably supports abearing 26 having an raxially projecting tip portion 26a.

In accordance with the invention, the side walls of the bearing 26 areconnected to the` side walls of the sleeve 19 by means of a flexibletubular sealing element 27 formed of silicone rubber or equivalentmaterial. The

tubular sealing element 27 -is received at one end inthe annular groove19C and at its other end about the open end portion of the bearing 26,the sealing element 27 being suitably bonded to both members 19 and 26so as to form air-tightseals therewith. p y

The axially projecting tip portion 426u `of the bearing' 26 receives andsupports a cap 28 which, in the illustrated apparatus, is generally inthe form of a cup. The cap 28 is slidably received on the bearing 26 andis normally held thereon by means of a bracket Z9 secured` to the bodyof the switch 11. As will be observed in Fig.` 1,

the cap 28 overlies the actuating plunger 16 of the switch 11 so thatvertical movements of the cap Ztl` will open and closetheI contacts ofthe switchll by moving the plunger 16. p p

' It will be Aobserved thatthe cap 17, sleeve 19, exible tube 27, andbearing 26 form an air-tight seal about the opening 1S in the coverplate 17, so that the entire mecha-` nism of the switch 11 ishermetically sealed within the casing 10. Actuation of the switch 11 maybe effected by rotating the control member 20 `to cause the eccentricspindle'portion 25 thereof `to move `through a circular path about theaxis of rotation of the control member. The bearing member 26, which issecured to the exible sealing element 27, `does not rotate but iscarried in a` assembly is in the control systems of aircraft, it isessen# tial to provide for the `wide variation in atmospheric pressureswhich occurs when an aircraft changes altitude, As will be observed inFig; 1, the flexible sealing element 27` fits loosely (provides morefworking materialand for axial adjustment) about the end of the controlIntiem-xh ber 20, forming a void space between the controly mem'-v-Patented Mar. 17, 195.9

ber 20 and the bearing 26. Thus, under normal cir- A cumstances, asubstantial reduction in atmospheric pressure outside of the casing 1Uwould tend to draw the sealing element 27 tightly against the endsurface of the control member 20. This is avoided in the improvedapparatus by filling the void space with a silicone oil or othersuitable tluid which displaces any air in the space in addition toacting as a lubricant for the free rotation of the control member 20. AnO-ring 30 seals the passage between the control member 2i) and the innerwalls of the bearing sleeve 19 so that oil is retained at the inner endsof the control member 2i] in the manner desired.

In the form of the invention shown in Fig. 3, a ilanged guide sleeve 31is received in the opening 18 in the Cover plate 17 and is securedthereto by solder or brazing, for example, so as to form an air-tightseal. A bearing sleeve 32 and control member 33 are supported in theguide sleeve 31 in such manner that the control member 33y projects overthe top of the switch 11 and actuating plunger 16. The controll member33 is positioned with* in the bearing sleeve 32, by means of a flange 34near the forward end of the control member 33, and by means of a collar35 received in a groove 36 near the opposite end of the control member.As will be observed in Fig. 3 the control member 33 and bearing sleeve32 are inserted as a unit within the guide sleeve 31 until the ilange ofthe sleeve 31 is engaged by a shoulder 32a of the bearing sleeve. Thebearing sleeve 32 is retained in its assembled position by a cap orother suitable means, not shown.

` At the inner end of the control member 33 isl an eccentric spindle 37which supports a combined bearing and end cap member 38. The cap 38 issubstantially the same diameter as the guide sleeve 31 and has anannular groove 38a therein corresponding generally to a similar annulargroove 31a in the sleeve 31. A llexble tubular sealing element 39 isreceived at one end over the inner end of guide sleeve 31 and isretained in the annular groove 31a in such manner as to provide anair-tight seal between the sleeve 31 and sealing member 39. The outerend of the sealing member 39 is received in a similar manner in theannular groove 38a of the end cap. The Void space surrounding the innerend of the control member 33 and bounded by the sealing element 39 isiilled with a suitable lubricating fluid such as silicone oil. An O-ring40 received in a groove 41 in the control member 33 seals the passagebetween the control member and the bearing sleeve 32 and retains thelubricating uid about the inner end of the control member.

The switch assembly of Fig. 3 is actuated by rotating a control member33, which causes the end cap 38 to be carried in a circular path by theeccentric spindle 37. The cap 38, being connected to the guide sleeve 31through the flexible sealing element 39, does not rotate but is merelycarried through a circular path of movement. The actuating plunger 16 ofswitch 11 follows the vertical movements of the cap 38 and effects theactuation of switch 11 in the manner desired.

In the modication of Fig. 4, the actuator mechanism includes a controlmember 50 having an end portion 51 with an end surface 51a disposed atan angle of less than 90 degrees with respect to the axis of rotation ofthe control member 50. At the extreme inner end of the control member 50is a spindle 52 disposed at right angles to the angular end surface 51aand mounting the inner race 53 of a ball bearing 54. The outer race 55of the bearing 54 carries an end cap 56 having an annular groove 56a inits outer surface. The control member 50 isk supported on the cover 17by means of a guide sleeve 57 and bearingk sleeve 58 and is sealed olffrom the interior of the switch casing by a exible tubular sealingelement 59 engaged at one end in the annular groove 56a and at its otherend in an annular groove 57a in the guide sleeve.

Rotation of the cap 56 is prevented by the sealing element 59, so thatupon rotation of the control member 50 the cap 56 merely wobbles ortilts from side to side.

In most cases the amplitude of movement of the cap 56 will be quitesmall, and accordingly, it may be desirable to magnify this movementsomewhat. In the illustrated apparatus this is accomplished by providinga lever 6i] which is secured to the cap 56 and extends radially outwardtherefrom. The end of the lever 60 overlies the actuating plunger 16 ofthe switch 11, and as the cap 56 is tilted from side to side the lever60 will be raised and lowered to move the plunger 16 and effect theopening and closing of the contacts of the switch 11. If desired therotation of the cap 56 may also be restricted by restricting the motionof the amplifying member 60 to one useful plane, with any suitablemeans, thereby taking some of the burden olf of the ilexible seal in thematter of resisting rotation of the cap. V

In the modification shown in Fig. 5, the switch 11 is mounted within acasing 70 having bearings 71, 7 2 mounted in opposite side walls. Thebearings 71, 72 journal a control member 73 which has an eccentricportion 73a located between the bearings. In accordance with theinvention, the bearings 71, 72 are mounted on the casing 79 in suchmanner as to form air-tight seals therewith. The inner end surfaces ofthe bearings 71, 72 are of conical form to t with the outwardly flaringend portions of a flexible tubular sealing element 74. The sealingelement 74 is relatively thin-walled and extends betweenthe bearings 71,72, in surrounding relation to the control member 73, and is bonded tothe bearings 71, 72y in such manner as to form air-tight seals at eachend.

Received over the outer surface of the flexible sealing" element 74,along the eccentric portion 73a of the control member 73 is a ring 75 ofmetal, plastic or other hard material. The ring 75 is generally alignedwith the actuating plunger 16, so that upon rotation of the control mem`ber 73 the ring 75 will be carried by the eccentric portion 73a in acircular path above the plunger 16. When the eccentric portion 73 movesthe ring 75 through the lower portion of its circular path the ring 75will engage and depress the plunger 16 to actuate switch 11.

In the modification of Fig. 6, the switch 11 is mounted within a casinghaving bearing members 81, 82 in opposite side walls thereof secured insuch manner as to form seals with the casing 80. The inner end portionsof the bearings 81, 82 have annular grooves 81a, 82a which engage' theopposite end portions of a flexible tubular sealing element 83. Thesealing element 83of the instant embodiment is relatively thick-walledand surrounds and forms a seal about the inner end portion of a controlmember 84. The control member 84 has an eccentric portion 84a positionedbetween the bearings 81, 82 and as will be observed in Fig. 6 theeccentric portion- 84a causes the adjacent side wall areas of the exibleelement 83 to be deformed outwardly. The switch 11 ofthe instantembodiment has an actuating plunger 16' having an enlarged pad 16 at itsupper end. 'Dhe pad 16" is positioned below and normally in spacedrelation to the flexible sealing element 83. However, as the controlmember 84 is rotated' to move the eccentric portion 84a thereof throughthe lower portion of its circular path the side wall of the sealingelement 83 will be deformed downwardly to engage and depress theactuating plunger 16".

Thus in all forms of the invention, a rotatable member having aneccentric portion extends into the interior of an hermetically sealedcasing but is sealed olf from the interior of the casing by means of aflexible tubular sealing element formed of silicone rubber or equivalentmaterial. When the control member is rotated the eccentric portionthereof acts either directly or through intermediate members to effectthe actuation of a switch within the cas,-v ing, and the sealing elementexes as necessary to accom` modate the movements of the eccentricportion. The new switch assembly is ideally suited for use in aircraft,for examp1e,.where unsealed portions of the assembly are apt to becomefrozen, since all parts of the assembly other than the control memberare eiectively sealed; and it is contemplated that the control memberwill be of suiciently rugged and durable construction to permit it to bebroken free when icing occurs. In addition, in the embodiments of Figs.1-4, the inner end portion of the control member is surrounded with alubricating fluid, such as silicone oil, which excludes moisture fromthe `inner portion of the control member. With this arrangement only theouter portion of the control member is likely to freeze, and this may bereadily broken free `with manual force.

As is readily apparent, the new switch assembly has several basic forms.Thus, in the embodiments of Figs. yl-4 the eccentric portion of thecontrol member effects the actuation of the switch through a cap membercarried bythe eccentric portion and caused to move in such manner as todepress switch actuating plunger 16. In the embodiments of Figs. 5 and 6the force is transmitted directly through the sealing element to theswitch actuating plunger. In the latter case the actuating force isdistributed over a relatively large area of the exible sealing element.In the embodiment of Fig. 5 this is accomplished by providing a ring 75of metal or hard plastic material about the outer wall of the flexibleelement 74. In the embodiment of Fig. 6 the actuating plunger 16' isprovided with an enlarged pad 16" at its upper end so that a large areaof `the sealing element S3 engages the pad to depress the plunger 16.

It should be understood that the speciiic embodiments herein shown anddescribed are intended to be illustrative only. Reference shouldtherefore be made `to `the following appended claims in determining thefull scope of the invention.

We claim:

l. An hermetically sealed switch and actuator `assembly comprising agenerally sealed casing having an opening therein, a switch mountedwithin said casing and having terminals extending through the casing,means to actuate said switch comprising a control member mounted in saidcasing for rotation and extending through said opening, said controlmember having an eccentric portion for eiecting the actuation of theswitch upon rotation of the member, a non-rotatable member formed ofnonresilient material and located adjacent an end of said controlmember, and means including a flexible tubular sealing element formed ofresilient material and open at both ends, said sealing element beingcontained within said casing and having at least one end secured infixed relation to the casing, the other end of said tubular sealingelement being sealingly and fixedly secured to said non-rotatablemember, said sealing element surrounding and forming a seal about saidopening and about said eccentric portion. t

2. An hermetically sealed switch and actuator assembly comprising agenerally sealed casing having an opening therein, a switch mountedwithin said casing and having terminals extending through the casing,means to actuate said switch comprising a control member mounted in saidcasing for rotation and extending through said opening, said controlmember having an eccentric portion for effecting the actuation of theswitch upon rotation of the member, a non-rotatable member formed ofnon-resilient material and located adjacent an end of said controlmember, and means including a flexible tubular sealing element formed ofresilient material and open at both ends, said sealing element beingcontained within said casing and having at least one end secured infixed relation to the casing, the other end of said tubular sealingelement being secured to said non-rotatable member, said sealing elementsurrounding and forming a seal about said opening and about saideccentric portion, said non-rotatable member com- 6 prising an endIpiecefreceived on the eccentric portion of said control member, saidsealingv element being sei-` cured to said end piece and forming a sealtherewith enclosing said eccentric portion, said eccentric portionacting through said end piece to actuate said switch upon rotation ofsaid control member.

3. The switch assembly of claim 2, characterized by said end pieceincluding a bearing member and an end cap supported by said bearingmember, said end cap engaging said switch to actuate the same uponrotation of said control member.`

4. The switch assembly of claim l, characterized by said casing havingmeans at opposite sides thereof for journaling said control member, saidcontrol member extending between the journal means and having aneccentric portion intermediate ts ends, said sealing element extendingbetween said journal means and forming a seal therewith, said controlmember being received internally of said tube, said non-rotatable membercomprising the journal means at one side of said casing. 5

5. The switch assembly of claim 4, characterized by said sealing elementcomprising a thin-walled tube and conforming intimately with saideccentric portion, and including a sleeve of non-resilient materialpositioned about a portion of said tube surrounding said eccentricportion, said sleeve being adapted to engage and actuate said switchupon rotation of said control member.

"6. The switch `assembly of claim 4, characterized by saidv sealingelement comprising a relatively thick-walled tube,f'said tube'` beingadapted to be deformed by said eccentric portion, and said switchincluding an actuatable member having'an enlarged head portion adaptedto be engaged and moved by deformed portions of said tube upon rotationof said control member.

7. An hermetically sealed switch assembly comprising a generally sealedcasing having an opening therein, a switch mounted within said casingand having terminals extending through the casing, a control memberextending through said opening and journaled by said casing, eccentricmeans actuated by rotation of said control member to effect theactuation of said switch, a non-rotatable member formed of non-resilientmaterial and located adjacent an end of said control member, and aflexible tubular sealing element formed of resilient material andsecured at one end about said opening and at its other end to saidnon-rotatable member, said sealing element sealing on? said controlmember from the interior of the casing and being movable with saideccentric means when said control member is rotated.

8. An hermetically sealed switch assembly comprising a generally sealedcasing having an opening therein, a switch mounted within said casingand having terminals extending through the casing, a control membermovably mounted on said casing and adapted upon movement to actuate saidswitch, a non-resilient member located adjacent an end of said controlmember, said control member being movable relative to the non-resilientmember, and a flexible tubular sealing element formed of resilientmaterial surrounding the opening and said control member and secured atone end about said opening and at its other end to saidl non-resilientmember, said sealing element sealing said control member oit from theinterior of said casing.

9. An hermetically sealed switch and actuator assembly comprising agenerally sealed casing having an opening therein, a switch mountedwithin said casing and having t terminals extending through the casing,means to actuate said switch comprising a control member mounted in saidcasing for rotation and extending through said opening, said controlmember having an eccentric portion for eiecting the actuation of theswitch upon rotation of the member, a sleeve received in the opening insaid casing and extending into the casing, the control member beingreceived in said sleeve and having its eccentric portion projectingbeyond the end of the sleeve within said casing, an end piece receivedon the eccentric portion of said control member, and means including aflexible sealingelement secured in xed relation to the casing andforming a seal about said opening and about said eccentric portion, saidsealing element comprising a sleeve of resilient material surroundingsaid control member and connected at one end to the inner end of saidsleeve and at the other end to said end piece, said sealing elementforming with said end piece a seal enclosing said eccentric portion,said eccentric portion acting through said end piece to actuate saidswitch upon rotation of said control member.

10. The switch assembly of claim 9, including an O- ring member forminga seal between the control member and sleeve, and characterized by thespace between the O-ring and bearing being iilled with a lubricant.

1l. An hermetically sealed switch and actuator assembly comprising agenerally sealed casing having an opening therein, a switch mountedwithin said casing and having terminals extending through the casing,means to actuate said switch comprising a control member mounted in saidcasing for rotation and extending through said opening, said controlmember having an eccentric portion for eiecting the actuation of theswitch upon rotation of the member, and means including a flexiblesealing element secured in fixed relation to the casing and forming aseal about said opening and about said eccentric portion, the eccentricportion of said control member comprising a surface at the inner endthereof disposed at an angle to the rotational axis of the controlmember, said end piece including bearing means mounted on said controlmember and positioned in contact with said surface, said flexiblesealing element comprising a tube secured at one end about the openingin said casing and at its other end to said end piece whereby to form aseal about said eccentric portion, said eccentric portion acting throughsaid bearing means to actuate said switch upon rotation of said controlmember.

12. The switch assembly of claim 11, characterized by said eccentricportion including a spindle disposed at right angles to said surface,and said bearing means including an anti-friction bearing having itsinner race mounted on said spindle, and said end piece including an endcap carried by the outer race of said bearing and having sealingengagement with the said other end of said sealing element.

13. The switch assembly of claim 12, including an arm carried by saidend cap and having actuating engagement with said switch.

14. An hermetically sealed switch assembly comprising a generally sealedcasing having an opening therein, a switch mounted within said casingand having terminals extending through the casing, a control membermovably mounted on said casing and adapted upon movement to actuate saidswitch, a flexible sealing element surrounding the opening and saidcontrol member and sealing said control member oi from the interior ofsaid casing, and means forming a -second seal between said controlmember and casing, said last-mentioned means and said sealing elementforming a sealed cavity for the reception of lubricating uid aboutportions of said control member.

References Cited in the le of this patent UNITED STATES PATENTS2,539,386 Albert Jan. 30, 1951 2,650,964 Razdow Sept. 1, 1953 2,725,445Bosch Nov. 29, 1955

